Optical annealing of peroxo-ferric intermediates in CYP17A1 and product formation.

Human cytochrome P450 CYP17A1 catalyzes the hydroxylation of pregnenolone and progesterone at the C17 position, with subsequent C17-C20 bond scission, to form dehydroepiandrosterone and androstenedione respectively. The first hydroxylation reaction is faster in HO than in DO, while the second carbon‑carbon bond scission event demonstrates an inverse solvent isotope effect, which is more pronounced for 17-hydroxy pregnenolone. In order to better understand the cause of this difference, we compared the optical absorption spectra of oxygenated CYP17A1 with the four substrates (pregnenolone, progesterone, 17-hydroxy pregnenolone and 17-hydroxy progesterone) in both HO and DO.

Nanodiscs for the study of membrane proteins.

Nanodiscs represent a versatile tool for studies of membrane proteins and protein-membrane interactions under native-like conditions. Multiple variations of the Nanodisc platform, as well as new experimental methods, have been recently developed to understand various aspects of structure, dynamics and functional properties of systems involved in signaling, transport, blood coagulation and many other critically important processes. In this mini-review, we focus on some of these exciting recent developments that utilize the Nanodisc platform.

Cryoradiolysis of oxygenated cytochrome P450 17A1 with lyase substrates generates expected products.

When subjected to γ-irradiation at cryogenic temperatures the oxygenated complexes of Cytochrome P450 CYP17A1 (CYP17A1) bound with either of the lyase substrates, 17α-Hydroxypregnenolone (17-OH PREG) or 17α-Hydroxyprogesterone (17-OH PROG) are shown to generate the corresponding lyase products, dehydroepiandrosterone (DHEA) and androstenedione (AD) respectively. The current study uses gas chromatography-mass spectrometry (GC/MS) to document the presence of the initial substrates and products in extracts of the processed samples. A rapid and efficient method for the simultaneous determination of residual substrate and products by GC/MS is described without derivatization of the products.

Theoretical and Experimental Studies of the Shock-Compressed Gas Parameters in the Welding Gap.

This work is devoted to the study of the processes that take place in the welding gap during explosive welding (EW). In the welding gap, when plates collide, a shock-compressed gas (SCG) region is formed, which moves at supersonic speed and has a high temperature that can affect the quality of the weld joint. Therefore, this work focuses on a detailed study of the parameters of the SCG.